The determination of the Euler-Poincare characteristic of a set can be based on observations of a digitized image of that set. In the present paper the correctness of the method is proved due to a strict integral-geometric approach. Our result also provides a link to the methods which are used in image analysis and are based on graph theory.

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During the sintering of multicomponent disperse systems prepared from mixtures of the components, a variety of solid-state reactions, phase formation or dissolution, and the occurrence of a liquid phase determine the densification and the final microstructure of the material.The results are presented of investigations on the systems WC~Co and Fe--Si, through the simultaneous application of dilatometry, differential thermal analysis and thermogravimetry, coupled with metallographic and microprobe analysis.A great variety of the materials used in the automotive and machine-building industries, in electronics or as tools in mechanical machining today are produced by powder metallurgy. One of the basic technological steps of this technique is the sintering process. Packed powders bond together when heated to temperatures in excess of approximately half of the absolute melting temperature. In general, powder metallurgical materials are of the multicomponent type. Their processing can start from mixed powders of differing chemistries or from prealloyed powders. The chemical interaction between the powder particles has to be taken into account for an understanding of the process occurring during sintering. Other factors influencing the behaviour during the thermal treatment result from the technology. Organic lubricants added to the powder mixture must evaporize completely at low temperatures, without cracking. Oxidizing or reducing processes occur, due to the interaction with the gaseous atmosphere in the furnace. Extensive experimental studies are necessary to optimize the sintering process and to define the conditions for processing a material with the desired microstructure and properties.The application of thermoanalytical methods to study sintering can give valuable information about chemical, microstructural and dimensional changes. In this study, dilatometry, thermogravimetry and differential thermal analysis are used to

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